logarithm

could you possibly help me out? I am stuck on two questions
the general term of an infinite sereis is tn= ( pie square) (3/11)^ n+1. how many terms must be added to reach a sum that is greater than 0.32?
t1 = (pie square) (3/11)2 = 0.233672181
r = (3/11)
Sm = a * (1-rm)/(1-r)
0.32 * 8/11 = 0.233672181 * (1-rm)
I know I have to use logarithm but I get confused!

can you...

Please Help!!!

could you possibly help me out? I am stuck on two questions
the general term of an infinite sereis is tn= ( pie square) (3/11)^ n+1. how many terms must be added to reach a sum that is greater than 0.32?
t1 = (pie square) (3/11)2 = 0.233672181
r = (3/11)
Sm = a * (1-rm)/(1-r)
0.32 * 8/11 = 0.233672181 * (1-rm)
I know I have to use logarithm but I get confused!